Sparse peer with transient participation

ABSTRACT

An example operation may include one or more of connecting, by a sparse peer, to a blockchain network of a plurality of peers controlled by orderers, selecting, by the sparse peer, a subset of data to be replicated, specifying, by the sparse peer, data selection filters based on the selected subset of the data, providing, by the sparse peer, the selection filters to the plurality of the peers, receiving, by the sparse peer, blocks matching the selection filters over a gossip protocol from the plurality of the peers, constructing, by the sparse peer, a local ledger of the sparse peer from the received blocks, and bootstrapping the sparse peer based on the local ledger.

TECHNICAL FIELD

This application generally relates to a database storage system, and more particularly, to a sparse peer with transient participation.

BACKGROUND

A centralized database stores and maintains data in one single database (e.g., database server) at one location. This location is often a central computer, for example, a desktop central processing unit (CPU), a server CPU, or a mainframe computer. Information stored on a centralized database is typically accessible from multiple different points. Multiple users or client workstations can work simultaneously on the centralized database, for example, based on a client/server configuration. A centralized database is easy to manage, maintain, and control, especially for purposes of security because of its single location. Within a centralized database, data redundancy is minimized as a single storing place of all data also implies that a given set of data only has one primary record.

However, a centralized database suffers from significant drawbacks. For example, a centralized database has a single point of failure. In particular, if there are no fault-tolerance considerations and a hardware failure occurs (for example a hardware, firmware, and/or a software failure), all data within the database is lost and work of all users is interrupted. In addition, centralized databases are highly dependent on network connectivity. As a result, the slower the connection, the amount of time needed for each database access is increased. Another drawback is the occurrence of bottlenecks when a centralized database experiences high traffic due to a single location. Furthermore, a centralized database provides limited access to data because only one copy of the data is maintained by the database. As a result, multiple devices cannot access the same piece of data at the same time without creating significant problems or risk overwriting stored data. Furthermore, because a database storage system has minimal to no data redundancy, data that is unexpectedly lost is very difficult to retrieve other than through manual operation from back-up storage.

Conventionally, a centralized database is limited by low search capability, lack of security and slow speed of transactions. As such, what is needed is a solution to overcome these significant drawbacks.

SUMMARY

One example embodiment provides a system that includes a processor and memory, wherein the processor is configured to perform one or more of connect to a blockchain network of a plurality of peers controlled by orderers, select a subset of data to be replicated, specify data selection filters based on the selected subset of the data, provide the selection filters to the plurality of the peers, receive blocks that match the selection filters over a gossip protocol from the plurality of the peers, construct a local ledger of the sparse peer from the received blocks, and bootstrap the sparse peer based on the local ledger.

Another example embodiment provides a system that includes a processor and memory, wherein the processor is configured to perform one or more of connect to a blockchain network of a plurality of peers controlled by orderers, configure the sparse peer to operate with a partial state of a chain to reduce a bootstrap time of the sparse peer, specify data selection filters based on the partial state of the chain, receive blocks that match the selection filters from the plurality of the peers via a gossip, store the blocks in a ledger of the sparse peer, determine if the ledger of the sparse peer is up-to-date based on the partial state of the chain, and in response to the determination that the ledger of the sparse peer is up-to-date, bootstrap the sparse peer.

Another example embodiment provides a system that includes a processor and memory, wherein the processor is configured to perform one or more of connect to a blockchain network of an organization configured to store assets, receive, from an ordering server, a block that contains a plurality of chaincode transactions that belong to plurality of peers of the blockchain network, apply a filter to the block, determine a recipient peer of the block in response to the application of the filter, receive a validation result of the block from the recipient peer, and commit the block to the blockchain network.

Another example embodiment provides a system that includes a processor and memory, wherein the processor is configured to perform one or more of connect to a blockchain network of an organization configured to store assets, receive, from an ordering server, a block that contains a plurality of chaincode transactions that belong to a plurality of peers of the blockchain, apply a filter to the block, determine a recipient peer of the block in response to the application of the filter, and receive a notification of validation and commitment of the block to the blockchain by the recipient peer.

Yet another example embodiment provides a method that includes one or more of connecting, by a sparse peer, to a blockchain network of a plurality of peers controlled by orderers, selecting, by the sparse peer, a subset of data to be replicated, specifying, by the sparse peer, data selection filters based on the selected subset of the data, providing, by the sparse peer, the selection filters to the plurality of the peers, receiving, by the sparse peer, blocks matching the selection filters over a gossip protocol from the plurality of the peers, constructing, by the sparse peer, a local ledger of the sparse peer from the received blocks, and bootstrapping the sparse peer based on the local ledger.

Yet another example embodiment provides a method that includes one or more of connecting, by a sparse peer, to a blockchain network of a plurality of peers controlled by orderers, configuring the sparse peer to operate with a partial state of a chain to reduce a bootstrap time of the sparse peer, specifying, by the sparse peer, data selection filters based on the partial state of the chain, receiving, by the sparse peer, blocks that match the selection filters from the plurality of the peers via a gossip, storing, by the sparse peer, the blocks in a ledger of the sparse peer, determining, by the sparse peer, if the ledger of the sparse peer is up-to-date based on the partial state of the chain, and in response to the determination that the ledger of the sparse peer is up-to-date, bootstrapping the sparse peer.

Yet another example embodiment provides a method that includes one or more of connecting, by a lead peer, to a blockchain network of an organization configured to store assets, receiving, by the lead peer, from an ordering server, a block that contains a plurality of chaincode transactions belonging to plurality of peers of the blockchain network, applying, by the lead peer, a filter to the block, determining, by the lead peer, a recipient peer of the block in response to the application of the filter, receiving, by the lead peer, a validation result of the block from the recipient peer, and committing, by the lead peer, the block to the blockchain network.

Yet another example embodiment provides a method that includes one or more of connecting, by a lead peer, to a blockchain network of an organization configured to store assets, receiving, by the lead peer, a block from an ordering server, that contains a plurality of chaincode transactions belonging to a plurality of peers of the blockchain, applying, by the lead peer, a filter to the block, determining, by the lead peer, a recipient peer of the block in response to the application of the filter, and receiving, by the lead peer, a notification of validation and commitment of the block to the blockchain by the recipient peer.

A further example embodiment provides a non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform one or more of connecting to a blockchain network of a plurality of peers controlled by orderers, selecting a subset of data to be replicated, specifying data selection filters based on the selected subset of the data, providing the selection filters to the plurality of the peers, receiving blocks matching the filters over a gossip protocol from the plurality of the peers, constructing a local ledger of the sparse peer from the received blocks, and bootstrapping the sparse peer based on the local ledger.

A further example embodiment provides a non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform one or more of connecting to a blockchain network of a plurality of peers controlled by orderers, configuring the sparse peer to operate with a partial state of a chain to reduce a bootstrap time of the sparse peer, specifying data selection filters based on the partial state of the chain, receiving blocks that match the selection filters from the plurality of the peers via a gossip, storing the blocks in a ledger of the sparse peer, determining if the ledger of the sparse peer is up-to-date based on the partial state of the chain, and in response to the determination that the ledger of the sparse peer is up-to-date, bootstrapping the sparse peer.

A further example embodiment provides a non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform one or more of connecting to a blockchain network of an organization configured to store assets, receiving, from an ordering server, a block that contains a plurality of chaincode transactions belonging to plurality of peers of the blockchain network, applying a filter to the block, determining a recipient peer of the block in response to the application of the filter, receiving a validation result of the block from the recipient peer, and committing the block to the blockchain network.

A further example embodiment provides a non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform one or more of connecting to a blockchain network of an organization configured to store assets, receiving a block from an ordering server that contains a plurality of chaincode transactions belonging to a plurality of peers of the blockchain, applying a filter to the block, determining a recipient peer of the block in response to the application of the filter, and receiving a notification of validation and commitment of the block to the blockchain by the recipient peer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a network diagram of a system including a database, according to example embodiments.

FIG. 1B illustrates a network diagram of a system including a database, according to example embodiments.

FIG. 1C illustrates a network diagram of a system including a database, according to example embodiments.

FIG. 1D illustrates a network diagram of a system including a database, according to example embodiments.

FIG. 2A illustrates an example peer node configuration, according to example embodiments.

FIG. 2B illustrates a further peer node configuration, according to example embodiments.

FIG. 3 illustrates a permissioned network, according to example embodiments.

FIG. 4A illustrates a flow diagram, according to example embodiments.

FIG. 4B illustrates a further flow diagram, according to example embodiments.

FIG. 4C illustrates a flow diagram, according to example embodiments.

FIG. 4D illustrates a further flow diagram, according to example embodiments.

FIG. 4E illustrates a flow diagram, according to example embodiments.

FIG. 4F illustrates a further flow diagram, according to example embodiments.

FIG. 4G illustrates a flow diagram, according to example embodiments.

FIG. 4H illustrates a further flow diagram, according to example embodiments.

FIG. 5A illustrates an example system configured to perform one or more operations described herein, according to example embodiments.

FIG. 5B illustrates a further example system configured to perform one or more operations described herein, according to example embodiments.

FIG. 5C illustrates a smart contract configuration among contracting parties and a mediating server configured to enforce the smart contract terms on the blockchain according to example embodiments.

FIG. 5D illustrates another additional example system, according to example embodiments.

FIG. 6A illustrates a process of new data being added to a database, according to example embodiments.

FIG. 6B illustrates contents a data block including the new data, according to example embodiments.

FIG. 7 illustrates an example system that supports one or more of the example embodiments.

DETAILED DESCRIPTION

It will be readily understood that the instant components, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of at least one of a method, apparatus, non-transitory computer readable medium and system, as represented in the attached figures, is not intended to limit the scope of the application as claimed but is merely representative of selected embodiments.

The instant features, structures, or characteristics as described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases “example embodiments”, “some embodiments”, or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment. Thus, appearances of the phrases “example embodiments”, “in some embodiments”, “in other embodiments”, or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In addition, while the term “message” may have been used in the description of embodiments, the application may be applied to many types of network data, such as, packet, frame, datagram, etc. The term “message” also includes packet, frame, datagram, and any equivalents thereof. Furthermore, while certain types of messages and signaling may be depicted in exemplary embodiments they are not limited to a certain type of message, and the application is not limited to a certain type of signaling.

Example embodiments provide methods, systems, components, non-transitory computer readable media, devices, and/or networks, which provide for implementing of a sparse peer node with transient participation in blockchain networks.

A decentralized database is a distributed storage system which includes multiple nodes that communicate with each other. A blockchain is an example of a decentralized database which includes an append-only immutable data structure resembling a distributed ledger capable of maintaining records between mutually untrusted parties. The untrusted parties are referred to herein as peers or peer nodes. Each peer maintains a copy of the database records and no single peer can modify the database records without a consensus being reached among the distributed peers. For example, the peers may execute a consensus protocol to validate blockchain storage transactions, group the storage transactions into blocks, and build a hash chain over the blocks. This process forms the ledger by ordering the storage transactions, as is necessary, for consistency. In a public or permission-less blockchain, anyone can participate without a specific identity. Public blockchains often involve native crypto-currency and use consensus based on various protocols such as Proof of Work (PoW). On the other hand, a permissioned blockchain database provides a system which can secure inter-actions among a group of entities which share a common goal, but which do not fully trust one another, such as businesses that exchange funds, goods, information, and the like.

A blockchain operates arbitrary, programmable logic, tailored to a decentralized storage scheme and referred to as “smart contracts” or “chaincodes.” In some cases, specialized chaincodes may exist for management functions and parameters which are referred to as system chaincode. Smart contracts are trusted distributed applications which leverage tamper-proof properties of the blockchain database and an underlying agreement between nodes which is referred to as an endorsement or endorsement policy. In general, blockchain transactions typically must be “endorsed” before being committed to the blockchain while transactions which are not endorsed are disregarded. A typical endorsement policy allows chaincode to specify endorsers for a transaction in the form of a set of peer nodes that are necessary for endorsement. When a client sends the transaction to the peers specified in the endorsement policy, the transaction is executed to validate the transaction. After validation, the transactions enter an ordering phase in which a consensus protocol is used to produce an ordered sequence of endorsed transactions grouped into blocks.

Nodes are the communication entities of the blockchain system. A “node” may perform a logical function in the sense that multiple nodes of different types can run on the same physical server. Nodes are grouped in trust domains and are associated with logical entities that control them in various ways. Nodes may include different types, such as a client or submitting-client node which submits a transaction-invocation to an endorser (e.g., peer), and broadcasts transaction-proposals to an ordering service (e.g., ordering node). Another type of node is a peer node which can receive client submitted transactions, commit the transactions and maintain a state and a copy of the ledger of blockchain transactions. Peers can also have the role of an endorser, although it is not a requirement. An ordering-service-node or orderer is a node running the communication service for all nodes, and which implements a delivery guarantee, such as a broadcast to each of the peer nodes in the system when committing transactions and modifying a world state of the blockchain, which is another name for the initial blockchain transaction which normally includes control and setup information.

A ledger is a sequenced, tamper-resistant record of all state transitions of a blockchain. State transitions may result from chaincode invocations (i.e., transactions) submitted by participating parties (e.g., client nodes, ordering nodes, endorser nodes, peer nodes, etc.). A transaction may result in a set of asset key-value pairs being committed to the ledger as one or more operands, such as creates, updates, deletes, and the like. The ledger includes a blockchain (also referred to as a chain) which is used to store an immutable, sequenced record in blocks. The ledger also includes a state database which maintains a current state of the blockchain. There is typically one ledger per channel. Each peer node maintains a copy of the ledger for each channel of which they are a member.

A chain is a transaction log which is structured as hash-linked blocks, and each block contains a sequence of N transactions where N is equal to or greater than one. The block header includes a hash of the block's transactions, as well as a hash of the prior block's header. In this way, all transactions on the ledger may be sequenced and cryptographically linked together. Accordingly, it is not possible to tamper with the ledger data without breaking the hash links. A hash of a most recently added blockchain block represents every transaction on the chain that has come before it, making it possible to ensure that all peer nodes are in a consistent and trusted state. The chain may be stored on a peer node file system (i.e., local, attached storage, cloud, etc.), efficiently supporting the append-only nature of the blockchain workload.

The current state of the immutable ledger represents the latest values for all keys that are included in the chain transaction log. Because the current state represents the latest key values known to a channel, it is sometimes referred to as a world state. Chaincode invocations execute transactions against the current state data of the ledger. To make these chaincode interactions efficient, the latest values of the keys may be stored in a state database. The state database may be simply an indexed view into the chain's transaction log, it can therefore be regenerated from the chain at any time. The state database may automatically be recovered (or generated if needed) upon peer node startup, and before transactions are accepted.

Some benefits of the instant solutions described and depicted herein include a method and system for implementation of a sparse peer node with transient participation in blockchain networks. The exemplary embodiments solve the issues of time and trust by extending features of a database such as immutability, digital signatures and being a single source of truth. The exemplary embodiments provide a solution for a sparse peer node with transient participation in blockchain networks blockchain-based network. The blockchain networks may be homogenous based on the asset type and rules that govern the assets based on the smart contracts.

Blockchain is different from a traditional database in that blockchain is not a central storage but rather a decentralized, immutable, and secure storage, where nodes must share in changes to records in the storage. Some properties that are inherent in blockchain and which help implement the blockchain include, but are not limited to, an immutable ledger, smart contracts, security, privacy, decentralization, consensus, endorsement, accessibility, and the like, which are further described herein. According to various aspects, the system for implementing of a sparse peer node with transient participation in blockchain networks is implemented due to immutable accountability, security, privacy, permitted decentralization, availability of smart contracts, endorsements and accessibility that are inherent and unique to blockchain. In particular, the blockchain ledger data is immutable and that provides for efficient method for creating a local ledger for a sparse peer in blockchain network. Also, use of the encryption in the blockchain provides security and builds trust. The smart contract manages the state of the asset to complete the life-cycle. The example blockchains are permission decentralized. Thus, each end user may have its own ledger copy to access. Multiple organizations (and peers) may be on-boarded on the blockchain network. The key organizations may serve as endorsing peers to validate the smart contract execution results, read-set and write-set. In other words, the blockchain inherent features provide for efficient implementation of a sparse peer.

One of the benefits of the example embodiments is that it improves the functionality of a computing system by implementing a sparse peer node. Through the blockchain system described herein, a computing system can perform functionality for implanting the sparse peer node that can be boot strapped using a subset of data from a local ledger in blockchain networks by providing access to capabilities such as distributed ledger, peers, encryption technologies, MSP, event handling, etc. Also, the blockchain enables to create a business network and make any users or organizations to on-board for participation. As such, the blockchain is not just a database. The blockchain comes with capabilities to create a Business Network of users and on-board/off-board organizations to collaborate and execute service processes in the form of smart contracts.

The example embodiments provide numerous benefits over a traditional database. For example, through the blockchain the embodiments provide for immutable accountability, security, privacy, permitted decentralization, availability of smart contracts, endorsements and accessibility that are inherent and unique to the blockchain.

Meanwhile, a traditional database could not be used to implement the example embodiments because it does not bring all parties on the business network, it does not create trusted collaboration and does not provide for an efficient storage of digital assets. The traditional database does not provide for a tamper proof storage and does not provide for preservation of properties of the digital assets being stored. Thus, the proposed method for operating a sparse peer node cannot be implemented in the traditional database.

Meanwhile, if a traditional database were to be used to implement the example embodiments, the example embodiments would have suffered from unnecessary drawbacks such as search capability, lack of security and slow speed of transactions. Additionally, the automated method for implementation of the sparse peer in the blockchain network would simply not be possible.

Accordingly, the example embodiments provide for a specific solution to a problem in the arts/field of using peers in the blockchain networks.

The example embodiments also change how data may be stored within a block structure of the blockchain. For example, a digital asset data may be securely stored within a certain portion of the data block (i.e., within header, data segment, or metadata). By storing the digital asset data within data blocks of a blockchain, the digital asset data may be appended to an immutable ledger (or a local ledger of the sparse peer) through a hash-linked chain of blocks. In some embodiments, the data block may be different than a traditional data block by having a personal data associated with the digital asset not stored together with the assets within a traditional block structure of a blockchain. By removing the personal data associated with the digital asset, the blockchain can provide the benefit of anonymity based on immutable accountability and security.

According to exemplary embodiments, each peer in Hyperledger Fabric is a full node, i.e., it holds a copy of the complete ledger for each channel of which the node is a member. Each committing node holds full block-storage, state DB (i.e., world state), history DB, etc. Bootstrap time is the time taken to create a new peer. The Bootstrap time is proportional to the length of the chain(s) (i.e., a number of blocks and a number of transactions per block). For example, Bitcoin bootstrap time is approximately 4 days (on parallel evolutionary computation cluster). Various scenarios may require sparse and transient peers on the blockchain network. Scaling up the peers in an organization to balance the load, which can improve transaction throughput and latency may be needed within an organization. Transient peers/participants (organization) that may join blockchain network any time to perform a transaction to get its work done and exit may be used in inter-organization communications. To perform certain short-lived CPU/IO intensive tasks such as analytics, reporting, and auditing query operations without affecting blockchain network's performance may be needed as an example of an intra-org implementation. Peer rejoining the network after a failure (intra and inter-org use case) may require a quick bootstrap.

Exemplary embodiments allow a sparse peer to work even with partial state of chain (without full chain) so that the sparse peer bootstrap time may be reduced. Depending on implementation, the sparse peer may select a subset of data it needs to replicate. For example, for scaling up the peers, an endorser for a subset of transactions by chaincodes/channels may only need the latest state of assets related to the subset of the chaincodes or the channels.

Short lived CPU/IO intensive tasks may be implemented as an auditor peer/chaincode. Depending on the audit criteria—e.g., time-period, all interactions with party Y, all assets with value over N$, etc. Analytics peer/chaincode—e.g., all historical data for a subset of keys matching a query. Fraud detection—e.g., all recent (within last N hours) transactions. The parse peer may use gossip to obtain selected data from peer(s), using filters within or outside organization and maintain its state. According to the exemplary embodiments, each sparse node could in itself be a source by having a bloom filter of data it holds and joining a gossip protocol. The lifecycle and resources used by such a peer may be verifiable by other members. The sparse peer may records filters for selecting data to replicate in the resource configuration (RSCC). Leaving or joining of the peer to a channel is recorded as a channel configuration. The sparse peer may serve as a gossip client for orderer(s) data and listens to blocks in-flight. The sparse peer may listen to in-flight transactions to enable early selection of transactions and keys to replicate. The sparse peer may only need to obtain the validation flags for a block from other peers—lightweight gossip.

A gossip protocol is a procedure or process of peer to peer communication that is based on the way the social networks disseminate information or how the epidemics spread. The gossip is a communication protocol. Distributed blockchain systems often use gossip protocols to solve problems that might be difficult to solve in other ways, either because the underlying network has an inconvenient structure, is extremely large, or because gossip solutions are the most efficient ones available.

According to one exemplary embodiment, conversion of a sparse peer to a full peer and vise-versa may be implemented. A sparse peer may be converted to the full peer by increasing the filter conditions one by one as follows:

Pass the filter as “Want Blocks Containing Chaincode-1 Transaction”, and once all blocks containing the chaincode transactions are received and validated-committed, pass the filter as “Want Block Containing Chaincode-1 and Chaincode-2 Transactions”, and so on until all blocks are received and all transactions are validated-committed.

When filter conditions change, using index maintained at other nodes, the system may determine which blocks (from the genesis block or block 1 to current blocks) meet pass the filter conditions and may send the past blocks accordingly.

Filter condition for the full peer would be “Want All Blocks”.

A full peer may be converted to a sparse peer by decreasing the filter conditions as follows:

Update the filter from “Want All Blocks” to “Want Blocks Containing Chaincode-1 Transaction”.

According to one exemplary embodiment, a distributed validation using sparse peers may be implemented. Within an organization, all nodes can trust each other. As a result, the nodes may divide the validation work and may share the validation results with each other. This may be achieved by using sparse peer and filters. For example, there are three peers (P1, P2, P3) in the same organization. There are 3 chaincodes/smart contracts C1, C2, C3. All peers execute all three chaincodes (e.g., for processing endorsement request in the case of Hyperledger Fabric). The filters may be passed by each peer when they join the organizations' network for the first time as follows:

Filter for the peer P1: Wants blocks containing chaincode1 (C1) transactions only;

Filter for the peer P2: Wants blocks containing chaincode2 (C2) transactions only; and

Filter for the peer P3: Wants blocks containing chaincode3 (C3) transactions only.

A block containing chaincode1, chaincode2, and chaincode3 transactions may be delivered to the leader peer P3 of the organization from the ordering service. The leader peer P3 applies the filter and determines to whom the block needs to be sent. As the block passes all filters' test, the block may be sent to all nodes. However, if the block contains only chaincode3 transaction, the block will not be delivered to the peer P1 and to the peer P2. These sparse peers have no way of verifying this block. The peer P1 validates only chaincode1 (C1) transactions (both endorsement validation and read/write set validation in case of Hyperledger Fabric). The peer P2 validates only chaincode2 (C2) transactions. The peer P3 validates only chaincode3 (C3) transactions. Each peer may share their validation results with others. When a peer receives validation results for all transactions in a block, the block is committed. Each peer stores all chaincode data.

According to another exemplary embodiment, sharding using sparse peers may be implemented. In general, sharding is a type of database (or ledger) partitioning that separates very large databases into smaller, faster, more easily managed parts called data shards. Within an organization, all nodes can trust each other. As a result, the system (i.e., a lead node) can shard the states and make each peer store a particular data set. This can be achieved using sparse peer and filters. For example, there are three peers (P1, P2, P3) in an organization 1. There are 3 chaincodes/smart contracts C1, C2, C3. The peer P1 executes the C1. The peer P2 executes the C2 and the peer P3 executes the C3. For an endorsement request for the C1, the request can only be submitted to the P1 as other peers are not running the C1 chaincodes. The filters may be passed by each peer when they join the network for the first time. Then the filters may be implemented as follows:

Filter for the peer P1: Interested in blocks containing chaincode1 (C1) transactions only;

Filter for the peer P2: Interested in blocks containing chaincode2 (C2) transactions only; and

Filter for the peer P3: Interested in blocks containing chaincode3 (C3) transactions only.

A block containing the chaincode1, the chaincode2 and the chaincode3 transactions is delivered to the leader peer P3 of the organization from the ordering service. The leader peer P3 may apply the filter and may determine to whom the block needs to be sent. If the block passes all filters test, the block is sent to all nodes. Otherwise, if the block contains, for example, only chaincode3 transaction, the block will not be delivered to the peer P1 and to the peer P2. The peer P1 validates only chaincode1 (C1) transactions (both endorsement validation and read/write set validation in case of Hyperledger Fabric). The peer P2 validates only chaincode1 (C2) transactions (both endorsement validation and read/write set validation in case of Hyperledger Fabric). The peer P3 validates only chaincode1 (C2) transactions (both endorsement validation and read/write set validation in case of Hyperledger Fabric). According to the exemplary embodiment, each peer commits the block based on the validation results. No sharing of validation information between peers may exist. Each peer stores only the respective chaincode data.

FIG. 1A illustrates a logic network diagram for implementing a sparse peer node in a blockchain network according to example embodiments.

Referring to FIG. 1A, the example network 100 includes a sparse peer 102 connected to a full peer node 103 within organization network 1. The sparse peer 102 may be connected to other full nodes 105 and 107 from organization 2 network. The sparse peer may have its own local ledger database 108 for storing selected blocks of data obtained from other peer nodes 103, 105 and 107 that are controlled by orderers 110. While this example shows only one sparse peer 102, multiple such nodes may be connected to the blockchain network. It should be understood that the sparse peer 102 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the sparse peer 102 disclosed herein. The sparse peer 102 may be a computing device or a server computer, or the like, and may include a processor 104, which may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or another hardware device. Although a single processor 104 is depicted, it should be understood that the sparse peer 102 may include multiple processors, multiple cores, or the like, without departing from a scope of the sparse peer 102 system.

The sparse peer 102 may also include a non-transitory computer readable medium 112 that may have stored thereon machine-readable instructions executable by the processor 104. Examples of the machine-readable instructions are shown as 114-126 and are further discussed below. Examples of the non-transitory computer readable medium 112 may include an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. For example, the non-transitory computer readable medium 112 may be a Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a hard disk, an optical disc, or other type of storage device.

The processor 104 may fetch, decode, and execute the machine-readable instructions 114 to connect to a blockchain network of a plurality of peers (103, 105, 107, etc.) controlled by orderers 110. The peers may belong to different organizations (e.g., Org 1 and Org 2). The blockchain may be managed by one or more devices and may be accessible by multiple participating nodes on a decentralized network. The blockchain network may be configured to use one or more smart contracts that manage data blocks for multiple participating nodes.

The processor 104 may fetch, decode, and execute the machine-readable instructions 116 to select a subset of data to be replicated. The processor 104 may fetch, decode, and execute the machine-readable instructions 118 to specify data selection filters based on the selected subset of the data. The processor 104 may fetch, decode, and execute the machine-readable instructions 120 to provide the selection filters to the plurality of the peers. The processor 104 may fetch, decode, and execute the machine-readable instructions 122 to receive blocks that match the selection filters over a gossip protocol from the plurality of the peers. The processor 104 may fetch, decode, and execute the machine-readable instructions 124 to construct a local ledger of the sparse peer from the received blocks. The processor 104 may fetch, decode, and execute the machine-readable instructions 126 to bootstrap the sparse peer based on the local ledger.

FIG. 1B illustrates a logic network diagram for implementing a sparse peer node in a blockchain network according to example embodiments.

Referring to FIG. 1B, the example network 101 includes a sparse peer 102 connected to a full peer node 103 within organization 1 network. The sparse peer 102 may be connected to other full nodes 105 and 107 from organization 2 network. The sparse peer may have its own local ledger database 108 for storing selected blocks of data obtained from other peer nodes 103, 105 and 107 that are controlled by orderers 110. While this example shows only one sparse peer 102, multiple such nodes may be connected to the blockchain network. It should be understood that the sparse peer 102 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the sparse peer 102 disclosed herein. The sparse peer 102 may be a computing device or a server computer, or the like, and may include a processor 104, which may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or another hardware device. Although a single processor 104 is depicted, it should be understood that the sparse peer 102 may include multiple processors, multiple cores, or the like, without departing from a scope of the sparse peer 102 system.

The sparse peer 102 may also include a non-transitory computer readable medium 112 that may have stored thereon machine-readable instructions executable by the processor 104. Examples of the machine-readable instructions are shown as 113-125 and are further discussed below. Examples of the non-transitory computer readable medium 112 may include an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. For example, the non-transitory computer readable medium 112 may be a Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a hard disk, an optical disc, or other type of storage device.

The processor 104 may fetch, decode, and execute the machine-readable instructions 113 to connect to a blockchain network of a plurality of peers (103, 105, 107, etc.) controlled by orderers 110. The peers may belong to different organizations (e.g., Org 1 and Org 2). The blockchain may be managed by one or more devices and may be accessible by multiple participating nodes on a decentralized network. The blockchain network may be configured to use one or more smart contracts that manage data blocks for multiple participating nodes.

The processor 104 may fetch, decode, and execute the machine-readable instructions 115 to configure the sparse peer 102 to operate with a partial state of a chain to reduce a bootstrap time of the sparse peer 102. The processor 104 may fetch, decode, and execute the machine-readable instructions 117 to specify data selection filters based on the partial state of the chain. The processor 104 may fetch, decode, and execute the machine-readable instructions 119 to receive blocks that match the selection filters from the plurality of the peers via a gossip. The processor 104 may fetch, decode, and execute the machine-readable instructions 121 to store the blocks in a ledger 108 of the sparse peer 102. The processor 104 may fetch, decode, and execute the machine-readable instructions 123 to determine if the ledger 108 of the sparse peer 102 is up-to-date based on the partial state of the chain. The processor 104 may fetch, decode, and execute the machine-readable instructions 125 to bootstrap the sparse peer in response to the determination that the ledger 108 of the sparse peer 102 is up-to-date.

FIG. 1C illustrates a logic network diagram for a distributed validation using sparse peer nodes in a blockchain network according to example embodiments.

Referring to FIG. 1C, the example network 111 includes a lead peer 135 connected to a sparse peer node 133 within organization 1 network. The lead peer 135 may be connected to other sparse nodes 129 and 127 from organization 2 network. The lead peer 135 may have its own local ledger database 108 for storing selected blocks of data obtained from ordering server 147. While this example shows only one lead peer 135, multiple such nodes may be connected to the blockchain network. It should be understood that the lead peer 135 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the lead peer 135 disclosed herein. The lead peer 135 may be a computing device or a server computer, or the like, and may include a processor 104, which may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or another hardware device. Although a single processor 104 is depicted, it should be understood that the lead peer 135 may include multiple processors, multiple cores, or the like, without departing from a scope of the lead peer 135 system.

The lead peer 135 may also include a non-transitory computer readable medium 112 that may have stored thereon machine-readable instructions executable by the processor 104. Examples of the machine-readable instructions are shown as 128-138 and are further discussed below. Examples of the non-transitory computer readable medium 112 may include an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. For example, the non-transitory computer readable medium 112 may be a Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a hard disk, an optical disc, or other type of storage device.

The processor 104 may fetch, decode, and execute the machine-readable instructions 128 to connect to a blockchain network of an organization configured to store assets. The peers of the blockchain may belong to different organizations (e.g., Org 1 and Org 2). The blockchain may be managed by one or more devices and may be accessible by multiple participating nodes on a decentralized network. The blockchain network may be configured to use one or more smart contracts that manage data blocks for multiple participating nodes.

The processor 104 may fetch, decode, and execute the machine-readable instructions 130 to receive, from an ordering server 110, a block that contains a plurality of chaincode transactions that belong to plurality of peers (e.g., 133, 129 and 127) of the blockchain network. The processor 104 may fetch, decode, and execute the machine-readable instructions 132 to apply a filter to the block. The processor 104 may fetch, decode, and execute the machine-readable instructions 134 to determine a recipient peer of the block, in response to the application of the filter. The processor 104 may fetch, decode, and execute the machine-readable instructions 136 to receive a validation result of the block from the recipient peer. The processor 104 may fetch, decode, and execute the machine-readable instructions 138 to commit the block to the blockchain network.

FIG. 1D illustrates a logic network diagram for sharding using sparse peer nodes in a blockchain network according to example embodiments.

Referring to FIG. 1D, the example network 131 includes a lead peer 135 connected to a sparse peer node 133 within organization 1 network. The lead peer 135 may be connected to other sparse peer nodes 129 and 127 from organization 2 network. The lead peer 135 may have its own local ledger database 108 for storing selected blocks of data obtained from the ordering server 147. While this example shows only one lead peer 135, multiple such nodes may be connected to the blockchain network. It should be understood that the lead peer 135 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the lead peer 135 disclosed herein. The lead peer 135 may be a computing device or a server computer, or the like, and may include a processor 104, which may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or another hardware device. Although a single processor 104 is depicted, it should be understood that the lead peer 135 may include multiple processors, multiple cores, or the like, without departing from a scope of the lead peer 135 system.

The lead peer 135 may also include a non-transitory computer readable medium 112 that may have stored thereon machine-readable instructions executable by the processor 104. Examples of the machine-readable instructions are shown as 137-145 and are further discussed below. Examples of the non-transitory computer readable medium 112 may include an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. For example, the non-transitory computer readable medium 112 may be a Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a hard disk, an optical disc, or other type of storage device.

The processor 104 may fetch, decode, and execute the machine-readable instructions 137 to connect to a blockchain network of an organization configured to store assets. The peers of the blockchain may belong to different organizations (e.g., Org 1 and Org 2). The blockchain may be managed by one or more devices and may be accessible by multiple participating nodes on a decentralized network. The blockchain network may be configured to use one or more smart contracts that manage data blocks for multiple participating nodes.

The processor 104 may fetch, decode, and execute the machine-readable instructions 139 to receive, from an ordering server, a block that contains a plurality of chaincode transactions that belong to a plurality of peers of the blockchain. The processor 104 may fetch, decode, and execute the machine-readable instructions 141 to apply a filter to the block. The processor 104 may fetch, decode, and execute the machine-readable instructions 143 to determine a recipient peer of the block, in response to the application of the filter. The processor 104 may fetch, decode, and execute the machine-readable instructions 145 to receive, a notification of validation and commitment of the block to the blockchain by the recipient peer (133, 129 or 127).

FIG. 2A illustrates a blockchain architecture configuration 200, according to example embodiments. Referring to FIG. 2A, the blockchain architecture 200 may include certain blockchain elements, for example, a group of blockchain nodes 202. The blockchain nodes 202 may include one or more nodes 204-210 (these four nodes are depicted by example only). These nodes participate in a number of activities, such as blockchain transaction addition and validation process (consensus). One or more of the blockchain nodes 204-210 may endorse transactions based on endorsement policy and may provide an ordering service for all blockchain nodes in the architecture 200. A blockchain node may initiate a blockchain authentication and seek to write to a blockchain immutable ledger stored in blockchain layer 216, a copy of which may also be stored on the underpinning physical infrastructure 214. The blockchain configuration may include one or more applications 224 which are linked to application programming interfaces (APIs) 222 to access and execute stored program/application code 220 (e.g., chaincode, smart contracts, etc.) which can be created according to a customized configuration sought by participants and can maintain their own state, control their own assets, and receive external information. This can be deployed as a transaction and installed, via appending to the distributed ledger, on all blockchain nodes 204-210.

The blockchain base or platform 212 may include various layers of blockchain data, services (e.g., cryptographic trust services, virtual execution environment, etc.), and underpinning physical computer infrastructure that may be used to receive and store new transactions and provide access to auditors which are seeking to access data entries. The blockchain layer 216 may expose an interface that provides access to the virtual execution environment necessary to process the program code and engage the physical infrastructure 214. Cryptographic trust services 218 may be used to verify transactions such as asset exchange transactions and keep information private.

The blockchain architecture configuration of FIG. 2A may process and execute program/application code 220 via one or more interfaces exposed, and services provided, by blockchain platform 212. The code 220 may control blockchain assets. For example, the code 220 can store and transfer data, and may be executed by nodes 204-210 in the form of a smart contract and associated chaincode with conditions or other code elements subject to its execution. As a non-limiting example, smart contracts may be created to execute reminders, updates, and/or other notifications subject to the changes, updates, etc. The smart contracts can themselves be used to identify rules associated with authorization and access requirements and usage of the ledger. For example, the sparse peer selection filter(s) information 226 may be processed by one or more processing entities (e.g., virtual machines) included in the blockchain layer 216. The result 228 may include data blocks matching the selection filter(s). The physical infrastructure 214 may be utilized to retrieve any of the data or information described herein.

Within chaincode, a smart contract may be created via a high-level application and programming language, and then written to a block in the blockchain. The smart contract may include executable code which is registered, stored, and/or replicated with a blockchain (e.g., distributed network of blockchain peers). A transaction is an execution of the smart contract code which can be performed in response to conditions associated with the smart contract being satisfied. The executing of the smart contract may trigger a trusted modification(s) to a state of a digital blockchain ledger. The modification(s) to the blockchain ledger caused by the smart contract execution may be automatically replicated throughout the distributed network of blockchain peers through one or more consensus protocols.

The smart contract may write data to the blockchain in the format of key-value pairs. Furthermore, the smart contract code can read the values stored in a blockchain and use them in application operations. The smart contract code can write the output of various logic operations into the blockchain. The code may be used to create a temporary data structure in a virtual machine or other computing platform. Data written to the blockchain can be public and/or can be encrypted and maintained as private. The temporary data that is used/generated by the smart contract is held in memory by the supplied execution environment, then deleted once the data needed for the blockchain is identified.

A chaincode may include the code interpretation of a smart contract, with additional features. As described herein, the chaincode may be program code deployed on a computing network, where it is executed and validated by chain validators together during a consensus process. The chaincode receives a hash and retrieves from the blockchain a hash associated with the data template created by use of a previously stored feature extractor. If the hashes of the hash identifier and the hash created from the stored identifier template data match, then the chaincode sends an authorization key to the requested service. The chaincode may write to the blockchain data associated with the cryptographic details. In FIG. 2A, selecting data blocks matching the filters may include execution of the smart contract. One function may be to commit of a transaction related to execution of the smart contract on the local ledger of the sparse peer, which may be provided to one or more of the nodes 204-210.

FIG. 2B illustrates an example of a transactional flow 250 between nodes of the blockchain in accordance with an example embodiment. Referring to FIG. 2B, the transaction flow may include a transaction proposal 291 sent by an application client node 260 to an endorsing peer node 281. The endorsing peer 281 may verify the client signature and execute a chaincode function to initiate the transaction. The output may include the chaincode results, a set of key/value versions that were read in the chaincode (read set), and the set of keys/values that were written in chaincode (write set). The proposal response 292 is sent back to the client 260 along with an endorsement signature, if approved. The client 260 assembles the endorsements into a transaction payload 293 and broadcasts it to an ordering service node 284. The ordering service node 284 then delivers ordered transactions as blocks to all peers 281-283 on a channel. Before committal to the blockchain, each peer 281-283 may validate the transaction. For example, the peers may check the endorsement policy to ensure that the correct allotment of the specified peers have signed the results and authenticated the signatures against the transaction payload 293.

Referring again to FIG. 2B, the client node 260 initiates the transaction 291 by constructing and sending a request to the peer node 281, which is an endorser. The client 260 may include an application leveraging a supported software development kit (SDK), such as NODE, JAVA, PYTHON, and the like, which utilizes an available API to generate a transaction proposal. The proposal is a request to invoke a chaincode function so that data can be read and/or written to the ledger (i.e., write new key value pairs for the assets). The SDK may serve as a shim to package the transaction proposal into a properly architected format (e.g., protocol buffer over a remote procedure call (RPC)) and take the client's cryptographic credentials to produce a unique signature for the transaction proposal.

In response, the endorsing peer node 281 may verify (a) that the transaction proposal is well formed, (b) the transaction has not been submitted already in the past (replay-attack protection), (c) the signature is valid, and (d) that the submitter (client 260, in the example) is properly authorized to perform the proposed operation on that channel. The endorsing peer node 281 may take the transaction proposal inputs as arguments to the invoked chaincode function. The chaincode is then executed against a current state database to produce transaction results including a response value, read set, and write set. However, no updates are made to the ledger at this point. In 292, the set of values, along with the endorsing peer node's 281 signature is passed back as a proposal response 292 to the SDK of the client 260 which parses the payload for the application to consume.

In response, the application of the client 260 inspects/verifies the endorsing peers' signatures and compares the proposal responses to determine if the proposal response is the same. If the chaincode only queried the ledger, the application would inspect the query response and would typically not submit the transaction to the ordering node service 284. If the client application intends to submit the transaction to the ordering node service 284 to update the ledger, the application determines if the specified endorsement policy has been fulfilled before submitting (i.e., did all peer nodes necessary for the transaction endorse the transaction). Here, the client may include only one of multiple parties to the transaction. In this case, each client may have their own endorsing node, and each endorsing node will need to endorse the transaction. The architecture is such that even if an application selects not to inspect responses or otherwise forwards an unendorsed transaction, the endorsement policy will still be enforced by peers and upheld at the commit validation phase.

After successful inspection, in step 293 the client 260 assembles endorsements into a transaction and broadcasts the transaction proposal and response within a transaction message to the ordering node 284. The transaction may contain the read/write sets, the endorsing peers' signatures and a channel ID. The ordering node 284 does not need to inspect the entire content of a transaction in order to perform its operation, instead the ordering node 284 may simply receive transactions from all channels in the network, order them chronologically by channel, and create blocks of transactions per channel.

The blocks of the transaction are delivered from the ordering node 284 to all peer nodes 281-283 on the channel. The transactions 294 within the block are validated to ensure any endorsement policy is fulfilled and to ensure that there have been no changes to ledger state for read set variables since the read set was generated by the transaction execution. Transactions in the block are tagged as being valid or invalid. Furthermore, in step 295 each peer node 281-283 appends the block to the channel's chain, and for each valid transaction the write sets are committed to current state database. An event is emitted, to notify the client application that the transaction (invocation) has been immutably appended to the chain, as well as to notify whether the transaction was validated or invalidated.

FIG. 3 illustrates an example of a permissioned blockchain network 300, which features a distributed, decentralized peer-to-peer architecture, and a certificate authority 318 managing user roles and permissions. In this example, the blockchain user 302 may submit a transaction to the permissioned blockchain network 310. In this example, the transaction can be a deploy, invoke or query, and may be issued through a client-side application leveraging an SDK, directly through a REST API, or the like. Trusted business networks may provide access to regulator systems 314, such as auditors (the Securities and Exchange Commission in a U.S. equities market, for example). Meanwhile, a blockchain network operator system of nodes 308 manage member permissions, such as enrolling the regulator system 310 as an “auditor” and the blockchain user 302 as a “client.” An auditor could be restricted only to querying the ledger whereas a client could be authorized to deploy, invoke, and query certain types of chaincode.

A blockchain developer system 316 writes chaincode and client-side applications. The blockchain developer system 316 can deploy chaincode directly to the network through a REST interface. To include credentials from a traditional data source 330 in chaincode, the developer system 316 could use an out-of-band connection to access the data. In this example, the blockchain user 302 connects to the network through a peer node 312. Before proceeding with any transactions, the peer node 312 retrieves the user's enrollment and transaction certificates from the certificate authority 318. In some cases, blockchain users must possess these digital certificates in order to transact on the permissioned blockchain network 310. Meanwhile, a user attempting to drive chaincode may be required to verify their credentials on the traditional data source 330. To confirm the user's authorization, chaincode can use an out-of-band connection to this data through a traditional processing platform 320.

FIG. 4A illustrates a flow diagram of an example method 400 of implementing a sparse peer in a blockchain network, according to example embodiments. Referring to FIG. 4A, the method 400 may include or more of the steps described below.

FIG. 4A illustrates a flow chart of an example method executed by the sparse peer 102 (see FIG. 1A). It should be understood that method 400 depicted in FIG. 4A may include additional operations and that some of the operations described therein may be removed and/or modified without departing from the scope of the method 400. The description of the method 400 is also made with reference to the features depicted in FIG. 1A for purposes of illustration. Particularly, the processor 104 of the sparse peer 102 may execute some or all of the operations included in the method 400.

With reference to FIG. 4A, at block 412, the processor 104 may connect to a blockchain network of a plurality of peers controlled by orderers. At block 414, the processor 104 may select a subset of data to be replicated. At block 416, the processor 104 may specify data selection filters based on the selected subset of the data. At block 418, the processor 104 may provide the selection filters to the plurality of the peers. At block 420, the processor 104 may receive blocks matching the selection filters over a gossip protocol from the plurality of the peers. At block 422, the processor 104 may construct a local ledger of the sparse peer from the received blocks. At block 424, the processor 104 may bootstrap the sparse peer based on the local ledger.

FIG. 4B illustrates a flow diagram of an example method 450 of operating a sparse peer node in a blockchain network, according to example embodiments. Referring to FIG. 4B, the method 450 may also include one or more of the following steps. At block 452, the processor 104 may selectively endorse transactions that can be satisfied by data of the local ledger. At block 454, the processor 104 may maintain a set of indexes to apply the selection filters and to select transactions that satisfy the selection filters. At block 456, the processor 104 may incrementally expand the selection filters to scale up an end state of the sparse peer. At block 458, the processor 104 may create a verifiable resource configuration to hold the selection filters and to communicate to the plurality of the peers an intent to receive data that matches the selection filters. At block 460, the processor 104 may identify when the local ledger is up-to-date and the sparse peer is ready to be bootstrapped.

FIG. 4C illustrates a flow diagram 410 of an example method of implementing a sparse peer in a blockchain network, according to example embodiments. Referring to FIG. 4C, the method 410 may include one or more of the steps described below.

FIG. 4C illustrates a flow chart of an example method executed by the sparse peer 102 (see FIG. 1B). It should be understood that method 410 depicted in FIG. 4C may include additional operations and that some of the operations described therein may be removed and/or modified without departing from the scope of the method 410. The description of the method 410 is also made with reference to the features depicted in FIG. 1B for purposes of illustration. Particularly, the processor 104 of the sparse peer 102 may execute some or all of the operations included in the method 410.

With reference to FIG. 4C, at block 411, the processor 104 may connect to a blockchain network of a plurality of peers controlled by orderers. At block 413, the processor 104 may configure the sparse peer to operate with a partial state of a chain to reduce a bootstrap time of the sparse peer. At block 415, the processor 104 may specify data selection filters based on the partial state of the chain. At block 417, the processor 104 may receive blocks that match the selection filters from the plurality of the peers via a gossip. At block 419, the processor 104 may store the blocks in a ledger of the sparse peer. At block 421, the processor 104 may determine if the ledger of the sparse peer is up-to-date based on the partial state of the chain. At block 423, the processor 104 may bootstrap the sparse peer in response to the determination that the ledger of the sparse peer is up-to-date.

FIG. 4D illustrates a flow diagram of an example method 461 of operating a sparse peer node in a blockchain network, according to example embodiments. Referring to FIG. 4D, the method 461 may also include one or more of the following steps. At block 462, the processor 104 may selectively endorse transactions executable based on the blocks from the ledger. At block 464, the processor 104 may maintain a set of indexes to apply the selection filters and to select transactions based on the selection filters. At block 466, the processor 104 may expand the selection filters to scale up the partial state of the chain. At block 468, the processor 104 may create a verifiable resource configuration to hold the selection filters and to notify the plurality of the peers to receive data that matches the selection filters. At block 470, the processor 104 may identify when the local ledger is up-to-date and the sparse peer is ready to be bootstrapped. At block 472, the processor 104 may continuously update the local ledger upon receiving the blocks matching the filters.

FIG. 4E illustrates a flow diagram 402 of an example method of a distributed validation using sparse peer in a blockchain network, according to example embodiments. Referring to FIG. 4E, the method 402 may include one or more of the steps described below.

FIG. 4E illustrates a flow chart of an example method executed by the lead peer 120 (see FIG. 1C). It should be understood that method 402 depicted in FIG. 4E may include additional operations and that some of the operations described therein may be removed and/or modified without departing from the scope of the method 402. The description of the method 402 is also made with reference to the features depicted in FIG. 1C for purposes of illustration. Particularly, the processor 104 of the lead peer 120 may execute some or all of the operations included in the method 402.

With reference to FIG. 4E, at block 425, the processor 104 may connect to a blockchain network of an organization configured to store assets. At block 427, the processor 104 may receive, from an ordering server, a block that contains a plurality of chaincode transactions belonging to plurality of peers of the blockchain network. At block 429, the processor 104 may apply a filter to the block. At block 431, the processor 104 may determine a recipient peer of the block in response to the application of the filter. At block 433, the processor 104 may receive a validation result of the block from the recipient peer. At block 435, the processor 104 may commit the block to the blockchain network.

FIG. 4F illustrates a flow diagram of an example method 471 of distributed validation using a sparse peer node in a blockchain network, according to example embodiments. Referring to FIG. 4F, the method 471 may also include one or more of the following steps. At block 473, the processor 104 may selectively endorse blocks that contain transactions that can be satisfied by data of a local ledger of the recipient peer. At block 475, the processor 104 may maintain a set of indexes to apply the filter to the data block. At block 477, the processor 104 may update a local ledger upon receiving blocks that match a filter of the lead peer.

FIG. 4G illustrates a flow chart of an example method executed by the lead peer 120 (see FIG. 1D). It should be understood that method 430 depicted in FIG. 4G may include additional operations and that some of the operations described therein may be removed and/or modified without departing from the scope of the method 430. The description of the method 430 is also made with reference to the features depicted in FIG. 1D for purposes of illustration. Particularly, the processor 104 of the lead peer 120 may execute some or all of the operations included in the method 430.

With reference to FIG. 4G, at block 434, the processor 104 may connect to a blockchain network of an organization configured to store assets. At block 437, the processor 104 may receive, from an ordering server, a block that contains a plurality of chaincode transactions belonging to plurality of peers of the blockchain network. At block 439, the processor 104 may apply a filter to the block. At block 441, the processor 104 may determine a recipient peer of the block in response to the application of the filter. At block 443, the processor 104 may receive a validation result of the block from the recipient peer.

FIG. 4H illustrates a flow diagram of an example method 480 of sharding using sparse peer nodes in a blockchain network, according to example embodiments. Referring to FIG. 4H, the method 480 may also include one or more of the following steps. At block 479, the processor 104 may selectively endorse blocks that contain transactions that can be satisfied by data of a local ledger of the recipient peer. At block 481, the processor 104 may maintain a set of indexes to apply the filter to the data block. At block 483, the processor 104 may send the block to each peer of the plurality of the peers of the blockchain if the block passes all filters test. At block 485, the processor 104 may send the block to the recipient peer configured to process transactions associated with a chaincode contained in the block. At block 487, the processor 104 may update a local ledger upon receiving blocks that match a filter of the lead peer.

FIG. 5A illustrates an example system 500 that includes a physical infrastructure 510 configured to perform various operations according to example embodiments. Referring to FIG. 5A, the physical infrastructure 510 includes a module 512 and a module 514. The module 514 includes a blockchain 520 and a smart contract 530 (which may reside on the blockchain 520), that may execute any of the operational steps 508 (in module 512) included in any of the example embodiments. The steps/operations 508 may include one or more of the embodiments described or depicted and may represent output or written information that is written or read from one or more smart contracts 530 and/or blockchains 520. The physical infrastructure 510, the module 512, and the module 514 may include one or more computers, servers, processors, memories, and/or wireless communication devices. Further, the module 512 and the module 514 may be a same module.

FIG. 5B illustrates an example system 540 configured to perform various operations according to example embodiments. Referring to FIG. 5B, the system 540 includes a module 512 and a module 514. The module 514 includes a blockchain 520 and a smart contract 530 (which may reside on the blockchain 520), that may execute any of the operational steps 508 (in module 512) included in any of the example embodiments. The steps/operations 508 may include one or more of the embodiments described or depicted and may represent output or written information that is written or read from one or more smart contracts 530 and/or blockchains 520. The physical infrastructure 510, the module 512, and the module 514 may include one or more computers, servers, processors, memories, and/or wireless communication devices. Further, the module 512 and the module 514 may be a same module.

FIG. 5C illustrates an example smart contract configuration among contracting parties and a mediating server configured to enforce the smart contract terms on the blockchain according to example embodiments. Referring to FIG. 5C, the configuration 550 may represent a communication session, an asset transfer session or a process or procedure that is driven by a smart contract 530 which explicitly identifies one or more user devices 552 and/or 556. The execution, operations and results of the smart contract execution may be managed by a server 554. Content of the smart contract 530 may require digital signatures by one or more of the entities 552 and 556 which are parties to the smart contract transaction. The results of the smart contract execution may be written to a blockchain 520 as a blockchain transaction. The smart contract 530 resides on the blockchain 520 which may reside on one or more computers, servers, processors, memories, and/or wireless communication devices.

FIG. 5D illustrates a common interface 560 for accessing logic and data of a blockchain, according to example embodiments. Referring to the example of FIG. 5D, an application programming interface (API) gateway 562 provides a common interface for accessing blockchain logic (e.g., smart contract 530 or other chaincode) and data (e.g., distributed ledger, etc.) In this example, the API gateway 562 is a common interface for performing transactions (invoke, queries, etc.) on the blockchain by connecting one or more entities 552 and 556 to a blockchain peer (i.e., server 554). Here, the server 554 is a blockchain network peer component that holds a copy of the world state and a distributed ledger allowing clients 552 and 556 to query data on the world state as well as submit transactions into the blockchain network where, depending on the smart contract 530 and endorsement policy, endorsing peers will run the smart contracts 530.

The above embodiments may be implemented in hardware, in a computer program executed by a processor, in firmware, or in a combination of the above. A computer program may be embodied on a computer readable medium, such as a storage medium. For example, a computer program may reside in random access memory (“RAM”), flash memory, read-only memory (“ROM”), erasable programmable read-only memory (“EPROM”), electrically erasable programmable read-only memory (“EEPROM”), registers, hard disk, a removable disk, a compact disk read-only memory (“CD-ROM”), or any other form of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such that the processor may read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an application specific integrated circuit (“ASIC”). In the alternative, the processor and the storage medium may reside as discrete components. For example, FIG. 6 illustrates an example computer system architecture 600, which may represent or be integrated in any of the above-described components, etc.

FIG. 6A illustrates a process 600 of a new block being added to a distributed ledger 630, according to example embodiments, and FIG. 6B illustrates contents of a block structure 650 for blockchain, according to example embodiments. Referring to FIG. 6A, clients (not shown) may submit transactions to blockchain nodes 621, 622, and/or 623. Clients may be instructions received from any source to enact activity on the blockchain 630. As an example, clients may be applications that act on behalf of a requester, such as a device, person or entity to propose transactions for the blockchain. The plurality of blockchain peers (e.g., blockchain nodes 621, 622, and 623) may maintain a state of the blockchain network and a copy of the distributed ledger 630. Different types of blockchain nodes/peers may be present in the blockchain network including endorsing peers which simulate and endorse transactions proposed by clients and committing peers which verify endorsements, validate transactions, and commit transactions to the distributed ledger 630. In this example, the blockchain nodes 621, 622, and 623 may perform the role of endorser node, committer node, or both.

The distributed ledger 630 includes a blockchain 632 which stores immutable, sequenced records in blocks, and a state database 634 (current world state) maintaining a current state of the blockchain 632. One distributed ledger 630 may exist per channel and each peer maintains its own copy of the distributed ledger 630 for each channel of which they are a member. The blockchain 632 is a transaction log, structured as hash-linked blocks where each block contains a sequence of N transactions. Blocks may include various components such as shown in FIG. 6B. The linking of the blocks (shown by arrows in FIG. 6A) may be generated by adding a hash of a prior block's header within a block header of a current block. In this way, all transactions on the blockchain 632 are sequenced and cryptographically linked together preventing tampering with blockchain data without breaking the hash links. Furthermore, because of the links, the latest block in the blockchain 632 represents every transaction that has come before it. The blockchain 632 may be stored on a peer file system (local or attached storage), which supports an append-only blockchain workload.

The current state of the blockchain 632 and the distributed ledger 632 may be stored in the state database 634. Here, the current state data represents the latest values for all keys ever included in the chain transaction log of the blockchain 632. Chaincode invocations execute transactions against the current state in the state database 634. To make these chaincode interactions extremely efficient, the latest values of all keys are stored in the state database 634. The state database 634 may include an indexed view into the transaction log of the blockchain 632, it can therefore be regenerated from the chain at any time. The state database 634 may automatically get recovered (or generated if needed) upon peer startup, before transactions are accepted.

Endorsing nodes receive transactions from clients and endorse the transaction based on simulated results. Endorsing nodes hold smart contracts which simulate the transaction proposals. When an endorsing node endorses a transaction, the endorsing nodes creates a transaction endorsement which is a signed response from the endorsing node to the client application indicating the endorsement of the simulated transaction. The method of endorsing a transaction depends on an endorsement policy which may be specified within chaincode. An example of an endorsement policy is “the majority of endorsing peers must endorse the transaction.” Different channels may have different endorsement policies. Endorsed transactions are forward by the client application to ordering service 610.

The ordering service 610 accepts endorsed transactions, orders them into a block, and delivers the blocks to the committing peers. For example, the ordering service 610 may initiate a new block when a threshold of transactions has been reached, a timer times out, or another condition. In the example of FIG. 6A, blockchain node 622 is a committing peer that has received a new data block 650 for storage on blockchain 630.

The ordering service 610 may be made up of a cluster of orderers. The ordering service 610 does not process transactions, smart contracts, or maintain the shared ledger. Rather, the ordering service 610 may accept the endorsed transactions and specifies the order in which those transactions are committed to the distributed ledger 630. The architecture of the blockchain network may be designed such that the specific implementation of ‘ordering’ (e.g., Solo, Kafka, BFT, etc.) becomes a pluggable component.

Transactions are written to the distributed ledger 630 in a consistent order. The order of transactions is established to ensure that the updates to the state database 634 are valid when they are committed to the network. Unlike a crypto-currency blockchain system (e.g., Bitcoin, etc.) where ordering occurs through the solving of a cryptographic puzzle, or mining, in this example the parties of the distributed ledger 630 may choose the ordering mechanism that best suits that network.

When the ordering service 610 initializes a new block 650, the new block 650 may be broadcast to committing peers (e.g., blockchain nodes 621, 622, and 623). In response, each committing peer validates the transaction within the new block 650 by checking to make sure that the read set and the write set still match the current world state in the state database 634. Specifically, the committing peer can determine whether the read data that existed when the endorsers simulated the transaction is identical to the current world state in the state database 634. When the committing peer validates the transaction, the transaction is written to the blockchain 632 on the distributed ledger 630, and the state database 634 is updated with the write data from the read-write set. If a transaction fails, that is, if the committing peer finds that the read-write set does not match the current world state in the state database 634, the transaction ordered into a block will still be included in that block, but it will be marked as invalid, and the state database 634 will not be updated.

Referring to FIG. 6B, a block 650 (also referred to as a data block) that is stored on the blockchain 632 of the distributed ledger 630 may include multiple data segments such as a block header 660, block data 670, and block metadata 680. It should be appreciated that the various depicted blocks and their contents, such as block 650 and its contents. Shown in FIG. 6B are merely for purposes of example and are not meant to limit the scope of the example embodiments. In some cases, both the block header 660 and the block metadata 680 may be smaller than the block data 670 which stores transaction data, however this is not a requirement. The block 650 may store transactional information of N transactions (e.g., 100, 500, 1000, 2000, 3000, etc.) within the block data 670. The block 650 may also include a link to a previous block (e.g., on the blockchain 632 in FIG. 6A) within the block header 660. In particular, the block header 660 may include a hash of a previous block's header. The block header 660 may also include a unique block number, a hash of the block data 670 of the current block 650, and the like. The block number of the block 650 may be unique and assigned in an incremental/sequential order starting from zero. The first block in the blockchain may be referred to as a genesis block which includes information about the blockchain, its members, the data stored therein, etc.

The block data 670 may store transactional information of each transaction that is recorded within the block 650. For example, the transaction data may include one or more of a type of the transaction, a version, a timestamp, a channel ID of the distributed ledger 630, a transaction ID, an epoch, a payload visibility, a chaincode path (deploy tx), a chaincode name, a chaincode version, input (chaincode and functions), a client (creator) identify such as a public key and certificate, a signature of the client, identities of endorsers, endorser signatures, a proposal hash, chaincode events, response status, namespace, a read set (list of key and version read by the transaction, etc.), a write set (list of key and value, etc.), a start key, an end key, a list of keys, a Merkel tree query summary, and the like. The transaction data may be stored for each of the N transactions.

In some embodiments, the block data 670 may also store data 672 which adds additional information to the hash-linked chain of blocks in the blockchain 632. Accordingly, the data 672 can be stored in an immutable log of blocks on the distributed ledger 630. Some of the benefits of storing such data 672 are reflected in the various embodiments disclosed and depicted herein.

The block metadata 680 may store multiple fields of metadata (e.g., as a byte array, etc.). Metadata fields may include signature on block creation, a reference to a last configuration block, a transaction filter identifying valid and invalid transactions within the block, last offset persisted of an ordering service that ordered the block, and the like. The signature, the last configuration block, and the orderer metadata may be added by the ordering service 610. Meanwhile, a committer of the block (such as blockchain node 622) may add validity/invalidity information based on an endorsement policy, verification of read/write sets, and the like. The transaction filter may include a byte array of a size equal to the number of transactions in the block data 670 and a validation code identifying whether a transaction was valid/invalid.

FIG. 7 is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the application described herein. Regardless, the computing node 700 is capable of being implemented and/or performing any of the functionality set forth hereinabove.

In computing node 700 there is a computer system/server 702, which is operational with numerous other general purposes or special purpose computing system environments or configurations. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with computer system/server 702 include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like.

Computer system/server 702 may be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks or implement particular abstract data types. Computer system/server 702 may be practiced in distributed cloud computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computer system storage media including memory storage devices.

As shown in FIG. 7, computer system/server 702 in cloud computing node 700 is shown in the form of a general-purpose computing device. The components of computer system/server 702 may include, but are not limited to, one or more processors or processing units 704, a system memory 706, and a bus that couples various system components including system memory 706 to processor 704.

The bus represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnects (PCI) bus.

Computer system/server 702 typically includes a variety of computer system readable media. Such media may be any available media that is accessible by computer system/server 702, and it includes both volatile and non-volatile media, removable and non-removable media. System memory 706, in one embodiment, implements the flow diagrams of the other figures. The system memory 706 can include computer system readable media in the form of volatile memory, such as random-access memory (RAM) 710 and/or cache memory 712. Computer system/server 702 may further include other removable/non-removable, volatile/non-volatile computer system storage media. By way of example only, storage system 714 can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a “hard drive”). Although not shown, a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a “floppy disk”), and an optical disk drive for reading from or writing to a removable, non-volatile optical disk such as a CD-ROM, DVD-ROM or other optical media can be provided. In such instances, each can be connected to the bus by one or more data media interfaces. As will be further depicted and described below, memory 706 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of various embodiments of the application.

Program/utility 716, having a set (at least one) of program modules 718, may be stored in memory 706 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data. Each of the operating system, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment. Program modules 718 generally carry out the functions and/or methodologies of various embodiments of the application as described herein.

As will be appreciated by one skilled in the art, aspects of the present application may be embodied as a system, method, or computer program product. Accordingly, aspects of the present application may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present application may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

Computer system/server 702 may also communicate with one or more external devices 720 such as a keyboard, a pointing device, a display 722, etc.; one or more devices that enable a user to interact with computer system/server 702; and/or any devices (e.g., network card, modem, etc.) that enable computer system/server 702 to communicate with one or more other computing devices. Such communication can occur via I/O interfaces 724. Still yet, computer system/server 702 can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via network adapter 726. As depicted, network adapter 726 communicates with the other components of computer system/server 702 via a bus. It should be understood that although not shown, other hardware and/or software components could be used in conjunction with computer system/server 702. Examples include, but are not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

Although an exemplary embodiment of at least one of a system, method, and non-transitory computer readable medium has been illustrated in the accompanied drawings and described in the foregoing detailed description, it will be understood that the application is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions as set forth and defined by the following claims. For example, the capabilities of the system of the various figures can be performed by one or more of the modules or components described herein or in a distributed architecture and may include a transmitter, receiver or pair of both. For example, all or part of the functionality performed by the individual modules, may be performed by one or more of these modules. Further, the functionality described herein may be performed at various times and in relation to various events, internal or external to the modules or components. Also, the information sent between various modules can be sent between the modules via at least one of: a data network, the Internet, a voice network, an Internet Protocol network, a wireless device, a wired device and/or via plurality of protocols. Also, the messages sent or received by any of the modules may be sent or received directly and/or via one or more of the other modules.

One skilled in the art will appreciate that a “system” could be embodied as a personal computer, a server, a console, a personal digital assistant (PDA), a cell phone, a tablet computing device, a Smartphone or any other suitable computing device, or combination of devices. Presenting the above-described functions as being performed by a “system” is not intended to limit the scope of the present application in any way but is intended to provide one example of many embodiments. Indeed, methods, systems and apparatuses disclosed herein may be implemented in localized and distributed forms consistent with computing technology.

It should be noted that some of the system features described in this specification have been presented as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, graphics processing units, or the like.

A module may also be at least partially implemented in software for execution by various types of processors. An identified unit of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions that may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module. Further, modules may be stored on a computer-readable medium, which may be, for instance, a hard disk drive, flash device, random access memory (RAM), tape, or any other such medium used to store data.

Indeed, a module of executable code could be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

It will be readily understood that the components of the application, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments is not intended to limit the scope of the application as claimed but is merely representative of selected embodiments of the application.

One having ordinary skill in the art will readily understand that the above may be practiced with steps in a different order, and/or with hardware elements in configurations that are different than those which are disclosed. Therefore, although the application has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent.

While preferred embodiments of the present application have been described, it is to be understood that the embodiments described are illustrative only and the scope of the application is to be defined solely by the appended claims when considered with a full range of equivalents and modifications (e.g., protocols, hardware devices, software platforms etc.) thereto. 

What is claimed is:
 1. A system, comprising: a processor of a sparse peer; a memory on which are stored machine readable instructions that when executed by the processor, cause the processor to: connect to a blockchain network of a plurality of peers controlled by orderers; select a subset of data to be replicated; specify data selection filters based on the selected subset of the data; provide the selection filters to the plurality of the peers; receive blocks that match the selection filters over a gossip protocol from the plurality of the peers; construct a local ledger of the sparse peer from the received blocks; and bootstrap the sparse peer based on the local ledger.
 2. The system of claim 1, wherein the instructions are further to cause the processor to selectively endorse transactions that can be satisfied by data of the local ledger.
 3. The system of claim 2, wherein the instructions are further to cause the processor to maintain a set of indexes to apply the selection filters and to select transactions that satisfy the selection filters.
 4. The system of claim 1, wherein the instructions are further to cause the processor to incrementally expand the selection filters to scale up an end state of the sparse peer.
 5. The system of claim 1, wherein the instructions are further to cause the processor to create a verifiable resource configuration to hold the selection filters and to communicate to the plurality of the peers an intent to receive data that matches the selection filters.
 6. The system of claim 1, wherein the instructions are further to cause the processor to identify when the local ledger is up-to-date and the sparse peer is ready to be bootstrapped.
 7. The system of claim 1, wherein the instructions are further to cause the processor to update the local ledger when the blocks that match the filters are received.
 8. A method, comprising: connecting, by a sparse peer, to a blockchain network of a plurality of peers controlled by orderers; selecting, by the sparse peer, a subset of data to be replicated; specifying, by the sparse peer, data selection filters based on the selected subset of the data; providing, by the sparse peer, the selection filters to the plurality of the peers; receiving, by the sparse peer, blocks matching the selection filters over a gossip protocol from the plurality of the peers; constructing, by the sparse peer, a local ledger of the sparse peer from the received blocks; and bootstrapping the sparse peer based on the local ledger.
 9. The method of claim 8, further comprising selectively endorsing transactions that can be satisfied by data of the local ledger.
 10. The method of claim 9, further comprising maintaining a set of indexes to apply the selection filters and to select transactions that satisfy the selection filters.
 11. The method of claim 8, further comprising incrementally expanding the selection filters to scale up an end state of the sparse peer.
 12. The method of claim 8, further comprising creating a verifiable resource configuration to hold the selection filters and to communicate to the plurality of the peers an intent to receive data matching the selection filters.
 13. The method of claim 8, further comprising identifying when the local ledger is up-to-date and the sparse peer is ready to be bootstrapped.
 14. The method of claim 8, further comprising updating the local ledger upon receiving the blocks matching the filters.
 15. A non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform: connecting to a blockchain network of a plurality of peers controlled by orderers; selecting a subset of data to be replicated; specifying data selection filters based on the selected subset of the data; providing the selection filters to the plurality of the peers; receiving blocks matching the filters over a gossip protocol from the plurality of the peers; constructing a local ledger of the sparse peer from the received blocks; and bootstrapping the sparse peer based on the local ledger.
 16. The non-transitory computer readable medium of claim 15 further comprising instructions, that when read by the processor, cause the processor to endorse transactions that can be satisfied by data of the local ledger.
 17. The non-transitory computer readable medium of claim 16 further comprising instructions, that when read by the processor, cause the processor to maintain a set of indexes to apply the selection filters and to select transactions that satisfy the selection filters.
 18. The non-transitory computer readable medium of claim 15 further comprising instructions, that when read by the processor, cause the processor to incrementally expand the selection filters to scale up an end state of the sparse peer.
 19. The non-transitory computer readable medium of claim 15 further comprising instructions, that when read by the processor, cause the processor to create a verifiable resource configuration to hold the selection filters and to communicate to the plurality of the peers an intent to receive data matching the selection filters.
 20. The non-transitory computer readable medium of claim 15 further comprising instructions, that when read by the processor, cause the processor to update the local ledger upon receiving the blocks matching the filters. 